Poor patient adherence to treatment limits the effectiveness of behavioral voice therapy. While patients can produce a target voice technique with clinician feedback, they experience adherence failure between therapy sessions characterized by an inability to replicate the target technique independently, forgetting to practice, and forgetting to use the technique all day. Patient self-efficacy (i.e. task-specific confidence) to overcome these challenges is poor. Problem: In our past research, provision of voice therapy videos on mobile MP4 devices significantly increased adherence and self-efficacy (i.e., task-specific confidence), and improved voice outcomes but not significantly so. Therefore, to assist patients in self-evaluating voice technique and remembering to use it, a novel iOS- based software application or app was developed in our laboratory that provides interactive voice quality feedback (jitter and cepstral peak prominence values), reminds patients to practice, models individualized practice via therapy recordings, and records all practice for direc tracking of adherence (without self-report). Objective: The aims of this project are to test the efficacy of our mobile app in affecting 1) improved voice therapy outcomes and 2) improved adherence and self-efficacy for adherence. Strategy: Sixty adults diagnosed with adducted hyperfunctional voice production and referred for resonant voice therapy at the University of Cincinnati Voice Clinic and Emory Voice Center will be randomized to one of two conditions: 1) resonant voice therapy supplemented by standard-of-care written homework instructions or 2) resonant voice therapy supplemented by the mobile voice therapy adherence app. All participants will record their practice on loaned iPods but only half will receive the app. For aim 1, outcome measures (VHI scores, acoustic and perceptual analysis of CAPE-V recordings) will be obtained prior to and following 4 sessions of treatment. For aim 2, adherence will be examined for frequency and duration of patient self-recordings and recordings obtained through app use. Self-efficacy will be tracked weekly through the Voice Therapy Self- Efficacy Scale. Group differences for both aims will be calculated via t-tests, and effects of self-efficacy and adherence on outcomes will be examined with regression analysis. Significance: This project will yield clinical tools and findings that translate directly to clinical voice care, are relevant across speech-language pathology interventions, expand knowledge of adherence and motor learning, and hold potential to increase voice therapy efficacy without increased cost.